Karstens out with inflamed shoulder
Karstens allowed two runs to Arizona in the first inning Tuesday night, both with two outs. The right-hander batted in the second inning, but didn't come out for the bottom half.
He was replaced by right-hander Jared Hughes, who had been warming up while Karstens was hitting.
The Pirates said Karstens, who was 0-1 with a 3.27 ERA his first two starts, will be evaluated when the team returns from Pittsburgh on Thursday.